J/MNRAS/444/1157 Members of ONC and Tau-Aur (Davies+, 2014)
Accretion discs as regulators of stellar angular momentum evolution in the
ONC and Taurus-Auriga.
Davies C.L., Gregory S.G., Greaves J.S.
<Mon. Not. R. Astron. Soc., 444, 1157-1176 (2014)>
=2014MNRAS.444.1157D 2014MNRAS.444.1157D
ADC_Keywords: Stars, pre-main sequence ; Accretion
Keywords: accretion, accretion discs- stars: formation- stars: late-type -
stars: pre-main-sequence - stars: rotation -
stars: variables: T Tauri, Herbig Ae/Be
Abstract:
In light of recent substantial updates to spectral type estimations
and newly established intrinsic colours, effective temperatures, and
bolometric corrections for pre-main sequence (PMS) stars, we
re-address the theory of accretion disc-regulated stellar angular
momentum (AM) evolution. We report on the compilation of a consistent
sample of fully convective stars within two of the most well-studied
and youngest, nearby regions of star formation: the Orion nebula
Cluster and Taurus-Auriga. We calculate the average specific stellar
AM (j*) assuming solid body rotation, using surface rotation periods
gathered from the literature and new estimates of stellar radii and
ages. We use published Spitzer IRAC fluxes to classify our stars as
Class II or Class III and compare their j* evolution. Our results
suggest that disc dispersal is a rapid process that occurs at a
variety of ages. We find a consistent j* reduction rate between the
Class II and Class III PMS stars which we interpret as indicating a
period of accretion disc-regulated AM evolution followed by
near-constant AM evolution once the disc has dissipated. Furthermore,
assuming our observed spread in stellar ages is real, we find that the
removal rate of j* during the Class II phase is more rapid than
expected by contraction at constant stellar rotation rate. A much more
efficient process of AM removal must exist, most likely in the form of
an accretion-driven stellar wind or other outflow from the star-disc
interaction region or extended disc surface.
Description:
In this paper, we focus on the evolution of specific stellar AM (j*)
in two of the youngest, nearby regions of star formation, namely the
ONC (1Myr; Hillenbrand, 1997AJ....113.1733H 1997AJ....113.1733H, Cat. J/AJ/113/1733) and
Taurus-Auriga (2.8Myr; White & Ghez, 2001ApJ...556..265W 2001ApJ...556..265W). The
well-studied nature and youthful ages of these two regions allows us
to split the sample according to their position in the
Hertzsprung-Russel (HR) diagram into fully convective and partially
convective samples.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 133 622 Stellar data for all members of the Orion Nebular
Cluster (ONC) not identified as binary or multiple
for which a spectral type exists in the literature
table2.dat 148 294 Stellar data for all members of Taurus-Auriga
not identified as binary or multiple for which
a spectral type exists in the literature
refs.dat 70 47 References
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 31 A31 --- Name SIMBAD name
33- 37 A5 --- SpT Adopted spectral type
39- 42 F4.2 --- e_SpT Error on SpT
44- 49 A6 --- ref1 Reference for SpT (1)
52- 57 F6.1 K Teff [2570/5390] Effective temperature (G2)
59- 64 F6.3 [Lsun] logL* [-2.1/1.6]?=- Bolometric stellar luminosity (G2)
66- 69 F4.2 Msun M* [0.1/2.9]?=- Stellar mass (G3)
71- 74 F4.2 Msun e_M* [0.01/1.1]?=- Error on M* (lower value)
76- 79 F4.2 Msun E_M* [0.01/1.1]?=- Error on M* (upper value)
81- 85 F5.2 Myr Age [0.03/44]?=- Age (G3)
87- 91 F5.2 Myr e_Age [0.02/19.5]?=- Error on Age (lower value)
93- 97 F5.2 Myr E_Age [0.03/32.5]?=- Error on Age (upper value)
99-103 F5.2 Rsun R* [0.27/8.26]?=- Stellar radius
105-108 F4.2 Rsun e_R* [0.05/1.19]?=- rms uncertainty on R*
110-114 F5.2 d Per [0.33/43.4]?=- Adopted rotation period
116-118 A3 --- n_Per Observed waveband for rotation period
measurement (opt, NIR or MIR)
120-123 A4 --- ref2 Reference for Per (2)
125-127 A3 --- Cl Source classification based on MIR excess (G4)
129 A1 --- Acc [AN] Accreting (A) / Not accreting (N) source
131-133 A3 --- Notes Reason, where applicable, for a star's
exclusion from the final analysis (G5)
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Note (1): Reference as follows:
D = Duncan (1993ApJ...406..172D 1993ApJ...406..172D)
D10 = Da Rio et al. 2010ApJ...722.1092D 2010ApJ...722.1092D, Cat. J/ApJ/722/1092
E = Edwards et al. (1993AJ....106..372E 1993AJ....106..372E)
H13 = Hillenbrand et al. (2013AJ....146...85H 2013AJ....146...85H, Cat. J/AJ/146/85)
LR = Luhman et al. (2000, cat. J/ApJ/540/1016)
Luc01 = Lucas et al., 2001MNRAS.326..695L 2001MNRAS.326..695L
P = Prosser & Stauffer 1995, private communication
RRL = Riddick et al. (2007MNRAS.381.1077R 2007MNRAS.381.1077R)
SHC-ir = Slesnick et al. (2004ApJ...610.1045S 2004ApJ...610.1045S), infrared spectral types
StE = H C. Stempels 2008, private communication, high dispersion spectra
Sta = K. Stassun 2005, private communication, low dispersion spectra
Note (2): References as follows:
E93 = Edwards et al. (1993AJ....106..372E 1993AJ....106..372E)
G95 = Gagne, Caillault & Stauffer (1995ApJ...445..280G 1995ApJ...445..280G, Cat. J/ApJ/445/280)
C96 = Choi & Herbst (1996AJ....111..283C 1996AJ....111..283C)
S99 = Stassun et al. (1999AJ....117.2941S 1999AJ....117.2941S, Cat. J/AJ/117/2941)
H00 = Herbst et al. (2000AJ....119..261H 2000AJ....119..261H)
C01 = Carpenter et al. (2001AJ....121.3160C 2001AJ....121.3160C, Cat. J/AJ/121/3160)
Re01 = Rebull (2001AJ....121.1676R 2001AJ....121.1676R, Cat. J/AJ/121/1676)
Rh01 = Rhode, Herbst & Mathieu (2001AJ....122.3258R 2001AJ....122.3258R)
H02 = Herbst et al. (2002A&A...396..513H 2002A&A...396..513H, Cat. J/A+A/396/513)
F09 = Frasca et al. (2009A&A...508.1313F 2009A&A...508.1313F, Cat. J/A+A/508/1313)
P09 = Parihar et al. (2009MNRAS.400..603P 2009MNRAS.400..603P, Cat. J/MNRAS/400/603)
R09 = Rodriguez-Ledesma et al. (2009A&A...502..883R 2009A&A...502..883R, Cat. J/A+A/502/883)
M11 = Morales-Calderon et al. (2011ApJ...733...50M 2011ApJ...733...50M, Cat. J/ApJ/733/50)
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name SIMBAD name
25- 29 A5 --- SpT Adopted spectral type
31- 34 F4.2 --- e_SpT [0.2/4] Error on SpT
36- 41 F6.1 K Teff [2390/6990]?=- Effective temperature (G2)
43- 47 F5.2 mag Vmag ?=- Johnson V magnitude
49- 52 F4.2 mag B-V ?=- Johnson B-V colour index
54- 58 F5.2 mag Icmag ?=- Cousins I magnitude
60- 63 F4.2 mag V-Ic ?=- Johnson-Cousins V-I colour index
65- 70 F6.3 [Lsun] logL* [-2.1/1.0]?=- Bolometric stellar luminosity (G2)
72- 75 F4.2 Msun M* [0.12/2.3]?=- Stellar mass (G3)
77- 80 F4.2 Msun e_M* [0.02/0.6]?=- Error on M* (lower value)
82- 85 F4.2 Msun E_M* [0.02/0.6]?=- Error on M* (upper value)
87- 91 F5.2 Myr Age [0.09/42]?=- Age (G3)
93- 97 F5.2 Myr e_Age [0.06/16]?=- Error on Age (lower value)
99-103 F5.2 Myr E_Age [0.2/30]?=- Error on Age (upper value)
105-108 F4.2 Rsun R* [0.2/4.4]?=- Stellar radius
110-113 F4.2 Rsun e_R* [0.03/0.7]?=- rms uncertainty on R*
115-121 F7.4 d Per [0.39/20]?=- Adopted rotation period
123-125 A3 --- Cl Source classification based on MIR excess
measurements (G4)
128-144 A17 --- r_SpT References for SpType, photometry, rotation
period and classification, in refs,dat file
146-148 A3 --- Notes Reason, where applicable, for a star's
exclusion from the final analysis (G5)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 50 A27 --- Aut Author's name
52- 70 A19 --- Com Comments
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Global notes:
Note (G2): calculated from SpT and optical photometry (see Sect. 3.1
and 3.2 for details).
Note (G3): calculated from Teff and logL* using Siess et al.
(2000A&A...358..593S 2000A&A...358..593S) PMS evolutionary models (see Sect. 3.3)
Note (G4): Source classification based on MIS excess includes classes
II (disced) III (discless)
Note (G5): Reason for a star's exclusion from the final analysis as follows:
a = not fully convective (see equation 6 and Section 2)
b = star lies outside the limits imposed in isochronal fitting (see Sect. 3.3)
c = no optical photometry available to calculate L* (see Sect. 3.2)
d = P>15d (see Sect. 3.5)
e = j*>jcrit (see Sect. 3.5)
f = no reliable rotation period available
g = able to calculate j* but not able to classify source as II or III
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Apr-2015